Instructions

Whisk 1½ cups (7½ ounces) all-purpose flour, ½ teaspoon baking powder, and ¼ teaspoon baking soda together in medium bowl. Using stand mixer fitted with paddle, beat 12 tablespoons softened unsalted butter, ¾ cup (5¼ ounces) light brown sugar, and ½ cup (3½ ounces) granulated sugar at medium speed until light and fluffy, about 3 minutes. Add ⅔ cup creamy peanut butter and ⅓ cup red miso and beat on medium speed until well incorporated, about 1 minute.
Scrape down bowl, then add 1 large egg and 1 teaspoon vanilla and mix until incorporated, about 1 minute. Reduce speed to low and slowly add flour mixture until combined, about 30 seconds. Cover dough and refrigerate for at least 2 hours or up to 24 hours.
Adjust oven rack to middle position and heat oven to 350 degrees. Line 2 rimmed baking sheets with parchment paper. Combine ¼ cup unsalted peanuts, finely chopped, and ¼ cup black or white sesame seeds in bowl. Divide dough into 18 equal portions, about 3 tablespoons each, and roll into balls. Working with 1 ball at a time, drop into peanut mixture and press lightly into mixture to coat 1 side of each dough ball. Transfer to prepared baking sheets, peanut mixture side up, spacing 2 inches apart.
Bake cookies 1 sheet at a time, storing second sheet in refrigerator, until edges are just set and beginning to brown, about 14 minutes, rotating sheet halfway through baking. Let cookies cool on sheet for 5 minutes, then transfer to wire rack and let cool completely. Serve.